Deffo tend to agree with the previous advice,, I had the same wooshing noise on a passat tdi, with no affect to the performance 'for a while' until one day the pipe connecting to the intercooler let go, THEN I noticed the performance drop, effectively cutting off the feed to the turbo. It was like driving an old non turbo diesel, no power at all. The noise your hearing really sounds like a split hose/pipe. And will eventually let go.......